1. Field of the Invention
The present invention relates in general to electric wheeled vehicles powered by batteries mounted thereon, and more particularly to floor structures of such electric vehicles. More specifically, the present invention is concerned with the floor structures of the electric vehicles, which are constructed to carry thereon batteries for powering the vehicles.
2. Description of the Prior Art
In electric vehicles of a type powered by batteries, the batteries are usually mounted on a floor structure of the vehicles. In order to securely mount the batteries on the floor structure, various measures have been proposed and put into practical use, some of which are shown in Japanese Patent First Provisional Publication 47-31318 and Japanese Utility Model First Provisional Publication 59-123966. In the measure of the publication 47-31318, side members, cross members and brackets, which are parts of a frame structure of the vehicle, are assembled to constitute a grid-shaped battery holding frame. The batteries are tightly disposed in the perforations of the battery holding frame respectively. While, in the measure of the publication 59-123966, many housings are defined by the floor structure for containing therein the batteries respectively. In this publication, a water jacket is also shown, which functions to keep the batteries at a given temperature.
However, the above-mentioned measures fail to consider the easiness with which the batteries are mounted to or dismounted from the vehicle. In fact, the work for mounting or dismounting the batteries onto or from the floor structure of the vehicle has been very difficult or at least troublesome because the work should be carried out within a very limited space under the vehicle floor. Furthermore, some of the conventional floor structures of such electric vehicles fail to exhibit satisfied resistance against a vehicle collision or the like.